This invention is directed to a process and apparatus for chemical conversion and, in particular, a process and apparatus for selective molecular modification for manufacture or destruction of chemicals.
Each chemical bond has a natural oscillating frequency at which the atoms move towards and away from each other. The natural oscillating frequency of a bond is constant at a given temperature and pressure and is dependent on the relative sizes of the bonded atoms, the geometry of the bonds, and the nature of adjacent bonds. Thus, a unique oscillating frequency is associated with each bond in a molecule, except where geometric symmetry exists. Where such symmetry exists, the symmetrical bonds have the same oscillating frequency.
A process and apparatus is provided for selectively breaking chemical bonds using an alternating current or pulsed direct current discharge having a suitable high frequency component. The continued application of a discharge at the suitable frequency will discourage the re-formation of the dissociated bond.
According to a broad aspect of the present invention there is provided a process for breaking a chemical bond in a molecule comprising: applying to the molecule a high voltage electrical discharge having a selected active high frequency component and at least sufficient amplitude to break the chemical bond.
According to a further broad aspect of the present invention there is provided an apparatus for breaking a chemical bond in a molecule, the molecule being in a gas or vapour state comprising: a reactor having a chamber for containing the molecule; and generator means for applying an electrical discharge current through the chamber, the discharge current having an active high frequency component which selectively break the chemical bond.
Chemical bond breaking is achieved by the use of a high frequency, high voltage alternating current or pulsed direct current discharge which is selected to have a waveform having a fast rise leading edge suitable for selectively breaking a selected bond in a particular type of molecule. Where there is a mixture of gasses, there will be selective breakage of the particular bond in the particular type of molecular target.
The fast rise portion of the waveform creates a range of high frequency components defined by the rate of change at each point on the slope in conjunction with the repetition rate (i.e. frequency) and the amplitude of the waveform. The time that the leading edge of a waveform is maintained at any given frequency combined with the voltage at that point give a potential energy transfer rate. To break a selected bond in a molecule, the leading edge of the waveform is selected to have a high frequency component which interferes with the bond, termed the xe2x80x9cactive frequencyxe2x80x9d or xe2x80x9cactive high frequency componentxe2x80x9d. This active frequency is applied at a suitable voltage and maintained for a sufficient time to transfer enough energy to the molecule to break the bond.
It is believed that the active high frequency component is close to a primary or harmonic of the natural oscillating frequency of the selected bond and therefore creates constructive interference with the oscillation of any of the bonds which are in phase with the high frequency component. It is believed that suitable active frequencies are at least in the megahertz range. The active frequency is applied at a suitable voltage and is maintained for a sufficient time to transfer enough energy to the molecule to break the bond. It is believed that the suitable voltage is at least three times the combined strength of the bonds to be broken. It is further believed that an avalanche effect is created wherein further selected bonds are broken by those broken through the application of the active frequency. In such an effect, the release of bond energy causes the separated atoms to be high in energy and to collide with other molecules that have bonds weakened from the application of the current. Due to the collision, the weakened bonds are broken. Since it is believed that the applied active frequency can be a harmonic of the natural oscillating frequency, it is believed that there are many frequencies that are suitable for interference with any one bond. By xe2x80x9charmonicxe2x80x9d in this disclosure it is meant not only integer multiples of the oscillating frequency of the bond, but also integer divisions. Many bond frequencies are of extremely high frequencies (in the Gigahertz range), and integer divisions of the resonating frequencies are easier to achieve than integer multiples.
In a reactor it is believed that substantially only the selected bonds are broken by applying a current having an active high frequency component and suitable voltage, since generally each bond in a molecule requires a unique frequency and minimum voltage for breakage. Selective breakage occurs even where other molecular species are present. However, due to ionization in the reactor and the impact of high energy atoms, some other bonds may be broken as well.
In an embodiment, a periodic wave form is generated having a leading edge selected to represent an active frequency for breaking a selected bond and sufficient voltage to break the bond once it is applied. In a continuous system, wherein molecules are being reacted and passed on, the flow rate of the molecules through the reactor must be considered and the voltage should be increased accordingly, to expose each portion of the gas or vapour containing the molecules to sufficient voltage to initiate bond breakage before the gas passes out of the reactor.
To carry out the process of the present invention, a current having a fast rise and sufficient voltage is applied to the gas or vapour form of a selected reactant. An active high frequency component for the bond which it is desired to break is determined and the waveform optimized by applying the discharge current to the reactant and adjusting the repetition rate or amplitude of the waveform or the inductance or capacitance of the circuit, transformer or reaction cell while monitoring the reaction by use of a means for chemical analysis, such as a mass spectrometer. In a preferred embodiment, the capacitance and inductance of the cell, circuit and transformer are maintained constant while the amplitude and repetition rate are adjusted to obtain the desired active frequency. Once determined, these parameters can be used for future chemical conversion involving that selected bond at substantially similar conditions of temperature and pressure in the reactor. Any changes in the voltage or the repetition rate of the applied discharge or changes in the inductance or capacitance of the circuit, transformer or reactor cell including any changes in reactor load, as pressure, temperature, flow rate or composition, require reoptimizeation of the waveform to re-establish the active high frequency component. Such readjustment can be made manually or, in some cases, by use of a circuit feedback arrangement. In addition, in reactors produced for the same reaction and with similar geometry, the circuit can be optimized once and incorporated into each further reactor without resetting.
The present process is also useful for selective breaking of geometrically symmetrical atomic bonds in a molecule by first selecting an active high frequency component for the first bond. Once that bond has been broken, the removal of a further bond requires that a different active frequency be selected. Since, the natural oscillating frequency of a bond is dependent upon bond geometry and the nature of adjacent atoms, it is believed that the breakage of the first of the symmetrical bonds is accomplished by applying current at the primary or harmonic of the bond so that constructive interference of the bond oscillation occurs. Once this bond is broken, the oscillating frequency of the remaining symmetrical bonds changes and requires a different harmonic or primary frequency for constructive interference. The process allows geometrically symmetrical atomic bonds in a molecule to be broken independently and in any desired number.
A reactor for chemical modification according to the invention is provided comprising a cell for containing a gaseous or vaporised form of molecular species to be reacted, or a gas or vapour comprising at least a portion of the molecular species to be reacted, and means for applying to the cell a high frequency, high voltage alternating or pulsed direct current discharge within a plasma or corona discharge. The discharge is selected to have a high frequency component and amplitude which will selectively break a bond in a molecule. In one embodiment, the reactor comprises means for applying to the cell a discharge comprising a waveform having an active frequency component.
In another embodiment a capacitive-inductive resonating circuit is used to produce a carrier waveform having the required active frequency for the chemical conversion. The circuit is powered by any suitable power supply or source. The resultant waveform can be an alternating current or a pulsed direct current having an active frequency component. In a preferred embodiment, the current is an alternating current discharge having an active frequency component and is preferably generated and maintained, by an electronic circuit employing a saturable transformer having a feedback winding. The high frequency component is produced by xe2x80x9cswitching onxe2x80x9d a transistor until the core of the transformer is magnetically saturated, as determined by the feedback winding or windings and the reaction cell. The xe2x80x9cswitch onxe2x80x9d initiates oscillation at the circuit resonance frequency and once initiated the energy from the core of the transformer maintains the reaction. In an alternate preferred embodiment, the current is a high voltage direct current discharge having the active high frequency component added thereto.
In the preferred embodiment, the reactor cell acts as the capacitance in a parallel resonant circuit with the secondary winding of the transformer forming the inductor. The capacitive and inductive characteristics of the cell and inductor are chosen such that the circuit is essentially resistive at the resonant, active frequency. Energy transfer produces some heat and causes chemical modification by interfering with and breaking a specific bond of a molecule. Altering the capacitance or inductance of the reactor and the repetition rate and amplitude of the applied waveform provides two means of selecting which bonds are to be broken.
Since the presence of gas or vapour alters the capacitance of the resonant circuit, the electronic circuit of the present invention is capable of compensating for changes in reactor loading such as the gas flow rate, gas density, gas composition or gas temperature by sensing the changes in the dielectric constant of the gas. Changes in the dielectric constant of the gas cause the current of the discharge in the reactor to change, and hence the feedback winding changes the operating parameters to maintain the required active frequency for specific chemical modification.
In an embodiment, an energy efficient reactor is provided wherein the transformer and electronics are impedance matched to the reactor circuit. Impedance matching in the reactor circuit can be provided by modifying the electrode geometry such as, for example, by winding a selected number of turns of a conductive element, such as wire, in communication with the high voltage or ground electrodes, by forming the high voltage electrode as a spiral having a predetermined pitch and length or by separating the electrodes by a selected distance.
In another embodiment, node reflection and wave form destruction in the reactor is minimized by, for example, selection of the length of the high voltage electrode and reactor length to prevent reflection of the wave and destructive interference thereof.
The apparatus of the present invention can be used in series with a plurality of heat exchangers of sequentially reducing temperatures which selectively condense, and thereby separate, various constituents of the fluid after treatment. It is preferred that a flowing stream of fluid be fed to the reactor such that a continuous process for chemical modification is provided. Since the application of current at the active frequency will discourage the reformation of selected bonds, this process can be used in combination with other reactors wherein streams of modified products can be caused to converge to react together chemically to create reaction products. Any reactor must be built having regard to the corrosion problems of the fluid to be introduced and formed in the reactor.
To increase the output of reaction products by the reactor, the length of the reactor can be extended or a plurality of reaction cells can be used in series or parallel. In such arrangements, an electrical control can be provided to detect malfunction in any portion of the reactor and cause the reactor to be shut down.
Since the molecular species to be reacted must be in a gas or vapour state, in an embodiment the reactor is constructed so as to be capable of vaporizing a liquid therein by application of heat or modification of internal pressure.